Robotic arm assemblies are typically quite sensitive to contact. Seemingly innocuous acts such as colliding with another body, work part, tool or fixture may produce sufficient damage to require repair. Often, the damaged component is an end effector attached to a tooling arm of a robotic system. An end effector is particularly susceptible to breakdowns because it is typically in constant motion, and many of the tasks it performs require such great precision that slight misalignments can produce significant error.
Once a robotic arm assembly is damaged, it is often quite difficult to repair it, resulting in excessive and often expensive down time. Repairing a damaged end effector typically requires the tooling arm to be dismantled from the robotic arm assembly and the end effector rebuilt in a machine shop. Once the end effector is rebuilt, a highly skilled technician is often required to reassemble the tooling arm to the robotic arm assembly, and to realign the end effector so that it performs according to its positional matrices.
The process of reconnecting the tooling arm to the robotic arm assembly typically requires numerous adjustments to account for positional variances caused by reassembly. There are robotic arm assemblies in the prior art which allow a tooling arm to be coupled and uncoupled without complex disassembly. However, most of these robotic arm assemblies are aimed at robotic tooling arms that handle tooling or masses greater than about 10 Kg, and most of these designs are quite mechanically complex. The current designs are typically not effective in protecting tooling and parts less than 1 Kg. Furthermore, many of these designs are not able to detect breakdowns of the end effector.
Also, minor collisions involving a robotic arm or an end effector can cause minor misalignments in the positioning of a tooling arm with respect to the robotic arm assembly. If these minor breakdowns are not detected, the end effector might produce faulty work pieces or it may cause more extensive damage to itself. Consequently, it is also of great importance that a robotic arm assembly sense and provide adequate warning of a misalignment.
Consequently, there is a need for a coupling device that will allow rapid and simple disassembly and assembly of a tooling arm from a robotic arm assembly, without loss of mechanical position of the tooling arm (i.e. no need to readjust the robotic system to account for differences in positioning of the tooling arm). There is also a need for a coupling device which includes a sensing mechanism that can detect a change in the relative position of the items being coupled.